1. Field of the Invention
The present invention relates to a storage control method, program, and apparatus that accesses, based on an input/output request from an upper apparatus, such as a server, a volume formed as a disk array from a plurality of storage devices having a RAID configuration and, particularly to a storage control method, program, and apparatus that monitors a deterioration in processing performance during operation and performs automatic recovery.
2. Description of the Related Arts
Conventionally, a disk array apparatus connected to a server on a network has been known as a storage area network (SAN) or a network attached storage (NAS). Such a disk array apparatus ensures high reliability by providing redundancy by a RAID (Redundant Arrays of Inexpensive Disks) configuration with a plurality of magnetic disk apparatuses being taken as storage devices so as to increase input/output performance and, at the same time, to allow recovery even if data loss occurs due to apparatus malfunction or the like.    [Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-039970    [Patent Document 2] Japanese Patent Laid-Open Publication No. 2000-293320
However, in such a disk array apparatus used as a network storage, many magnetic disk apparatuses are used as storage devices, all of which are basically ensured the same performance, but actually individual magnetic disk apparatuses have variations in performance to some extent. The performance of a particular magnetic disk apparatus may not cause a failure but may be deteriorated more than that of other magnetic disk apparatuses. It is not until a report from a user of the system who has noticed a delay in processing time at a client or server that troubleshooting for investigating and handling a cause for deterioration in performance is started. In such a case, possible causes for deterioration in performance are wide-ranging other than the disk array apparatus, such as a server or client on the network. In troubleshooting, all of such possible causes in that range are isolated from each other one by one. Even if a particular magnetic disk apparatus provided in the disk array apparatus is the cause for deterioration in performance, this poses a problem such that it takes a lot of time and trouble until that magnetic disk apparatus is found to be the cause and then the trouble is solved. According to the present invention to provide a storage control method, program, and apparatus that monitors the performance of the entire volume formed of a plurality of storage devices, such as disk apparatuses, and automatically recovers the performance when the performance is determined as having been deteriorated.